Anacostia sp.

Description and remarks. Three specimens (S266205, S266208, S266218) assignable to Anacostia (not figured) were recovered from the Catefica mesofossil flora. Cells of seed and fruit surface are distinctive for Anacostia, but the preservation does not allow a species level assignment.

Affinity and other occurrences. Anacostia was first described based on fruits, seeds and associated pollen from the Early Cretaceous of Maryland and Virginia, USA (Anacostia marylandensis E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN, A. virginiensis E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN) and from Portugal (Anacostia portugallica E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN, Anacostia teixeirae E.M.FRIIS, P.R.CRANE et K.R.PEDERSEN) (Friis et al. 1997). The genus is characterized by its one-seed fruits and exotestal seeds that have a crystalliferous seed coat and the inner layer of testa with strongly undulate walls. The four species also share the regular occurrence of trichotomocolpate, and occasionally monocolpate, pollen on the stigma and fruit surface. The monocolpate pollen indicates a relationship to non-eudicot angiosperms and the presence of an embryo with two cotyledons allows a monocot affinity to be rejected (Friis et al. 2015b). A possible affinity with Austrobaileyales was suggested by Friis et al. (1997) and has also been inferred based on several phylogenetic analyses by Doyle and Endress (e.g., Doyle and Endress 2014). However, there are critical features of Anacostia, such as the crystalliferous exotesta and the trichotomocolpate pollen, that are not consistent with the characters of extant taxa of Austrobaileyales, and relationship to other early diverging angiosperm lineages, for example among magnoliids (e.g., Canellales) cannot be ruled out.

Only three specimens of Anacostia have been recovered in the Catefica mesofossil flora, so far. This relative rarity contrasts with occurrences of the genus in the Buarcos, Famalicão and Vale de Água mesofossil floras where fruits and seeds of Anacostia are abundant.